1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38#include "opt_inet.h"
39#include "opt_inet6.h"
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/dirent.h>
44#include <sys/jail.h>
45#include <sys/kernel.h>
46#include <sys/lock.h>
47#include <sys/malloc.h>
48#include <sys/mbuf.h>
49#include <sys/mount.h>
50#include <sys/mutex.h>
51#include <sys/proc.h>
52#include <sys/rmlock.h>
53#include <sys/refcount.h>
54#include <sys/signalvar.h>
55#include <sys/socket.h>
56#include <sys/vnode.h>
57
58#include <netinet/in.h>
59#include <net/radix.h>
60
61#include <rpc/types.h>
62#include <rpc/auth.h>
63
64static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
65
66#if defined(INET) || defined(INET6)
67static struct radix_node_head *vfs_create_addrlist_af(
68		    struct radix_node_head **prnh, int off);
69#endif
70static int	vfs_free_netcred(struct radix_node *rn, void *w);
71static void	vfs_free_addrlist_af(struct radix_node_head **prnh);
72static int	vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
73		    struct export_args *argp);
74static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *);
75
76/*
77 * Network address lookup element
78 */
79struct netcred {
80	struct	radix_node netc_rnodes[2];
81	uint64_t netc_exflags;
82	struct	ucred *netc_anon;
83	int	netc_numsecflavors;
84	int	netc_secflavors[MAXSECFLAVORS];
85};
86
87/*
88 * Network export information
89 */
90struct netexport {
91	struct	netcred ne_defexported;		      /* Default export */
92	struct 	radix_node_head	*ne4;
93	struct 	radix_node_head	*ne6;
94};
95
96/*
97 * Build hash lists of net addresses and hang them off the mount point.
98 * Called by vfs_export() to set up the lists of export addresses.
99 */
100static int
101vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
102    struct export_args *argp)
103{
104	struct netcred *np;
105	struct radix_node_head *rnh;
106	int i;
107	struct radix_node *rn;
108	struct sockaddr *saddr, *smask = NULL;
109#if defined(INET6) || defined(INET)
110	int off;
111#endif
112	int error;
113
114	KASSERT(argp->ex_numsecflavors > 0,
115	    ("%s: numsecflavors <= 0", __func__));
116	KASSERT(argp->ex_numsecflavors < MAXSECFLAVORS,
117	    ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
118
119	/*
120	 * XXX: This routine converts from a uid plus gid list
121	 * to a `struct ucred' (np->netc_anon).  This
122	 * operation is questionable; for example, what should be done
123	 * with fields like cr_uidinfo and cr_prison?  Currently, this
124	 * routine does not touch them (leaves them as NULL).
125	 */
126	if (argp->ex_addrlen == 0) {
127		if (mp->mnt_flag & MNT_DEFEXPORTED) {
128			vfs_mount_error(mp,
129			    "MNT_DEFEXPORTED already set for mount %p", mp);
130			return (EPERM);
131		}
132		np = &nep->ne_defexported;
133		np->netc_exflags = argp->ex_flags;
134		np->netc_anon = crget();
135		np->netc_anon->cr_uid = argp->ex_uid;
136		crsetgroups(np->netc_anon, argp->ex_ngroups,
137		    argp->ex_groups);
138		np->netc_anon->cr_prison = &prison0;
139		prison_hold(np->netc_anon->cr_prison);
140		np->netc_numsecflavors = argp->ex_numsecflavors;
141		bcopy(argp->ex_secflavors, np->netc_secflavors,
142		    sizeof(np->netc_secflavors));
143		MNT_ILOCK(mp);
144		mp->mnt_flag |= MNT_DEFEXPORTED;
145		MNT_IUNLOCK(mp);
146		return (0);
147	}
148
149#if MSIZE <= 256
150	if (argp->ex_addrlen > MLEN) {
151		vfs_mount_error(mp, "ex_addrlen %d is greater than %d",
152		    argp->ex_addrlen, MLEN);
153		return (EINVAL);
154	}
155#endif
156
157	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
158	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
159	saddr = (struct sockaddr *) (np + 1);
160	if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
161		goto out;
162	if (saddr->sa_family == AF_UNSPEC || saddr->sa_family > AF_MAX) {
163		error = EINVAL;
164		vfs_mount_error(mp, "Invalid saddr->sa_family: %d");
165		goto out;
166	}
167	if (saddr->sa_len > argp->ex_addrlen)
168		saddr->sa_len = argp->ex_addrlen;
169	if (argp->ex_masklen) {
170		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
171		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
172		if (error)
173			goto out;
174		if (smask->sa_len > argp->ex_masklen)
175			smask->sa_len = argp->ex_masklen;
176	}
177	rnh = NULL;
178	switch (saddr->sa_family) {
179#ifdef INET
180	case AF_INET:
181		if ((rnh = nep->ne4) == NULL) {
182			off = offsetof(struct sockaddr_in, sin_addr) << 3;
183			rnh = vfs_create_addrlist_af(&nep->ne4, off);
184		}
185		break;
186#endif
187#ifdef INET6
188	case AF_INET6:
189		if ((rnh = nep->ne6) == NULL) {
190			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
191			rnh = vfs_create_addrlist_af(&nep->ne6, off);
192		}
193		break;
194#endif
195	}
196	if (rnh == NULL) {
197		error = ENOBUFS;
198		vfs_mount_error(mp, "%s %s %d",
199		    "Unable to initialize radix node head ",
200		    "for address family", saddr->sa_family);
201		goto out;
202	}
203	RADIX_NODE_HEAD_LOCK(rnh);
204	rn = (*rnh->rnh_addaddr)(saddr, smask, &rnh->rh, np->netc_rnodes);
205	RADIX_NODE_HEAD_UNLOCK(rnh);
206	if (rn == NULL || np != (struct netcred *)rn) {	/* already exists */
207		error = EPERM;
208		vfs_mount_error(mp,
209		    "netcred already exists for given addr/mask");
210		goto out;
211	}
212	np->netc_exflags = argp->ex_flags;
213	np->netc_anon = crget();
214	np->netc_anon->cr_uid = argp->ex_uid;
215	crsetgroups(np->netc_anon, argp->ex_ngroups,
216	    argp->ex_groups);
217	np->netc_anon->cr_prison = &prison0;
218	prison_hold(np->netc_anon->cr_prison);
219	np->netc_numsecflavors = argp->ex_numsecflavors;
220	bcopy(argp->ex_secflavors, np->netc_secflavors,
221	    sizeof(np->netc_secflavors));
222	return (0);
223out:
224	free(np, M_NETADDR);
225	return (error);
226}
227
228/* Helper for vfs_free_addrlist. */
229/* ARGSUSED */
230static int
231vfs_free_netcred(struct radix_node *rn, void *w)
232{
233	struct radix_node_head *rnh = (struct radix_node_head *) w;
234	struct ucred *cred;
235
236	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, &rnh->rh);
237	cred = ((struct netcred *)rn)->netc_anon;
238	if (cred != NULL)
239		crfree(cred);
240	free(rn, M_NETADDR);
241	return (0);
242}
243
244#if defined(INET) || defined(INET6)
245static struct radix_node_head *
246vfs_create_addrlist_af(struct radix_node_head **prnh, int off)
247{
248
249	if (rn_inithead((void **)prnh, off) == 0)
250		return (NULL);
251	RADIX_NODE_HEAD_LOCK_INIT(*prnh);
252	return (*prnh);
253}
254#endif
255
256static void
257vfs_free_addrlist_af(struct radix_node_head **prnh)
258{
259	struct radix_node_head *rnh;
260
261	rnh = *prnh;
262	RADIX_NODE_HEAD_LOCK(rnh);
263	(*rnh->rnh_walktree)(&rnh->rh, vfs_free_netcred, rnh);
264	RADIX_NODE_HEAD_UNLOCK(rnh);
265	RADIX_NODE_HEAD_DESTROY(rnh);
266	rn_detachhead((void **)prnh);
267	prnh = NULL;
268}
269
270/*
271 * Free the net address hash lists that are hanging off the mount points.
272 */
273void
274vfs_free_addrlist(struct netexport *nep)
275{
276	struct ucred *cred;
277
278	if (nep->ne4 != NULL)
279		vfs_free_addrlist_af(&nep->ne4);
280	if (nep->ne6 != NULL)
281		vfs_free_addrlist_af(&nep->ne6);
282
283	cred = nep->ne_defexported.netc_anon;
284	if (cred != NULL) {
285		crfree(cred);
286		nep->ne_defexported.netc_anon = NULL;
287	}
288
289}
290
291/*
292 * High level function to manipulate export options on a mount point
293 * and the passed in netexport.
294 * Struct export_args *argp is the variable used to twiddle options,
295 * the structure is described in sys/mount.h
296 * The do_exjail argument should be true if *mp is in the mountlist
297 * and false if not.  It is not in the mountlist for the NFSv4 rootfs
298 * fake mount point just used for exports.
299 */
300int
301vfs_export(struct mount *mp, struct export_args *argp, bool do_exjail)
302{
303	struct netexport *nep;
304	struct ucred *cr;
305	struct prison *pr;
306	int error;
307	bool new_nep;
308
309	if ((argp->ex_flags & (MNT_DELEXPORT | MNT_EXPORTED)) == 0)
310		return (EINVAL);
311
312	if ((argp->ex_flags & MNT_EXPORTED) != 0 &&
313	    (argp->ex_numsecflavors < 0
314	    || argp->ex_numsecflavors >= MAXSECFLAVORS))
315		return (EINVAL);
316
317	error = 0;
318	pr = curthread->td_ucred->cr_prison;
319	lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
320	nep = mp->mnt_export;
321	if (argp->ex_flags & MNT_DELEXPORT) {
322		if (nep == NULL) {
323			error = ENOENT;
324			goto out;
325		}
326		MNT_ILOCK(mp);
327		if (mp->mnt_exjail != NULL && mp->mnt_exjail->cr_prison != pr &&
328		    pr == &prison0) {
329			MNT_IUNLOCK(mp);
330			/* EXDEV will not get logged by mountd(8). */
331			error = EXDEV;
332			goto out;
333		} else if (mp->mnt_exjail != NULL &&
334		    mp->mnt_exjail->cr_prison != pr) {
335			MNT_IUNLOCK(mp);
336			/* EPERM will get logged by mountd(8). */
337			error = EPERM;
338			goto out;
339		}
340		MNT_IUNLOCK(mp);
341		if (mp->mnt_flag & MNT_EXPUBLIC) {
342			vfs_setpublicfs(NULL, NULL, NULL);
343			MNT_ILOCK(mp);
344			mp->mnt_flag &= ~MNT_EXPUBLIC;
345			MNT_IUNLOCK(mp);
346		}
347		vfs_free_addrlist(nep);
348		mp->mnt_export = NULL;
349		free(nep, M_MOUNT);
350		nep = NULL;
351		MNT_ILOCK(mp);
352		cr = mp->mnt_exjail;
353		mp->mnt_exjail = NULL;
354		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
355		MNT_IUNLOCK(mp);
356		if (cr != NULL) {
357			atomic_subtract_int(&pr->pr_exportcnt, 1);
358			crfree(cr);
359		}
360	}
361	if (argp->ex_flags & MNT_EXPORTED) {
362		new_nep = false;
363		MNT_ILOCK(mp);
364		if (mp->mnt_exjail == NULL) {
365			MNT_IUNLOCK(mp);
366			if (do_exjail && nep != NULL) {
367				vfs_free_addrlist(nep);
368				memset(nep, 0, sizeof(*nep));
369				new_nep = true;
370			}
371		} else if (mp->mnt_exjail->cr_prison != pr) {
372			MNT_IUNLOCK(mp);
373			error = EPERM;
374			goto out;
375		} else
376			MNT_IUNLOCK(mp);
377		if (nep == NULL) {
378			nep = malloc(sizeof(struct netexport), M_MOUNT,
379			    M_WAITOK | M_ZERO);
380			mp->mnt_export = nep;
381			new_nep = true;
382		}
383		if (argp->ex_flags & MNT_EXPUBLIC) {
384			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0) {
385				if (new_nep) {
386					mp->mnt_export = NULL;
387					free(nep, M_MOUNT);
388				}
389				goto out;
390			}
391			new_nep = false;
392			MNT_ILOCK(mp);
393			if (do_exjail && mp->mnt_exjail == NULL) {
394				mp->mnt_exjail = crhold(curthread->td_ucred);
395				atomic_add_int(&pr->pr_exportcnt, 1);
396			}
397			mp->mnt_flag |= MNT_EXPUBLIC;
398			MNT_IUNLOCK(mp);
399		}
400		if (argp->ex_numsecflavors == 0) {
401			argp->ex_numsecflavors = 1;
402			argp->ex_secflavors[0] = AUTH_SYS;
403		}
404		if ((error = vfs_hang_addrlist(mp, nep, argp))) {
405			if (new_nep) {
406				mp->mnt_export = NULL;
407				free(nep, M_MOUNT);
408			}
409			goto out;
410		}
411		MNT_ILOCK(mp);
412		if (do_exjail && mp->mnt_exjail == NULL) {
413			mp->mnt_exjail = crhold(curthread->td_ucred);
414			atomic_add_int(&pr->pr_exportcnt, 1);
415		}
416		mp->mnt_flag |= MNT_EXPORTED;
417		MNT_IUNLOCK(mp);
418	}
419
420out:
421	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
422	/*
423	 * Once we have executed the vfs_export() command, we do
424	 * not want to keep the "export" option around in the
425	 * options list, since that will cause subsequent MNT_UPDATE
426	 * calls to fail.  The export information is saved in
427	 * mp->mnt_export, so we can safely delete the "export" mount option
428	 * here.
429	 */
430	vfs_deleteopt(mp->mnt_optnew, "export");
431	vfs_deleteopt(mp->mnt_opt, "export");
432	return (error);
433}
434
435/*
436 * Get rid of credential references for this prison.
437 */
438void
439vfs_exjail_delete(struct prison *pr)
440{
441	struct mount *mp;
442	struct ucred *cr;
443	int error, i;
444
445	/*
446	 * Since this function is called from prison_cleanup() after
447	 * all processes in the prison have exited, the value of
448	 * pr_exportcnt can no longer increase.  It is possible for
449	 * a dismount of a file system exported within this prison
450	 * to be in progress.  In this case, the file system is no
451	 * longer in the mountlist and the mnt_exjail will be free'd
452	 * by vfs_mount_destroy() at some time.  As such, pr_exportcnt
453	 * and, therefore "i", is the upper bound on the number of
454	 * mnt_exjail entries to be found by this function.
455	 */
456	i = atomic_load_int(&pr->pr_exportcnt);
457	KASSERT(i >= 0, ("vfs_exjail_delete: pr_exportcnt negative"));
458	if (i == 0)
459		return;
460	mtx_lock(&mountlist_mtx);
461tryagain:
462	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
463		MNT_ILOCK(mp);
464		if (mp->mnt_exjail != NULL &&
465		    mp->mnt_exjail->cr_prison == pr) {
466			MNT_IUNLOCK(mp);
467			error = vfs_busy(mp, MBF_MNTLSTLOCK | MBF_NOWAIT);
468			if (error != 0) {
469				/*
470				 * If the vfs_busy() fails, we still want to
471				 * get rid of mnt_exjail for two reasons:
472				 * - a credential reference will result in
473				 *   a prison not being removed
474				 * - setting mnt_exjail NULL indicates that
475				 *   the exports are no longer valid
476				 * The now invalid exports will be deleted
477				 * when the file system is dismounted or
478				 * the file system is re-exported by mountd.
479				 */
480				cr = NULL;
481				MNT_ILOCK(mp);
482				if (mp->mnt_exjail != NULL &&
483				    mp->mnt_exjail->cr_prison == pr) {
484					cr = mp->mnt_exjail;
485					mp->mnt_exjail = NULL;
486				}
487				MNT_IUNLOCK(mp);
488				if (cr != NULL) {
489					crfree(cr);
490					i--;
491				}
492				if (i == 0)
493					break;
494				continue;
495			}
496			cr = NULL;
497			lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
498			MNT_ILOCK(mp);
499			if (mp->mnt_exjail != NULL &&
500			    mp->mnt_exjail->cr_prison == pr) {
501				cr = mp->mnt_exjail;
502				mp->mnt_exjail = NULL;
503				mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
504				MNT_IUNLOCK(mp);
505				vfs_free_addrlist(mp->mnt_export);
506				free(mp->mnt_export, M_MOUNT);
507				mp->mnt_export = NULL;
508			} else
509				MNT_IUNLOCK(mp);
510			lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
511			if (cr != NULL) {
512				crfree(cr);
513				i--;
514			}
515			mtx_lock(&mountlist_mtx);
516			vfs_unbusy(mp);
517			if (i == 0)
518				break;
519			goto tryagain;
520		}
521		MNT_IUNLOCK(mp);
522	}
523	mtx_unlock(&mountlist_mtx);
524}
525
526/*
527 * Set the publicly exported filesystem (WebNFS). Currently, only
528 * one public filesystem is possible in the spec (RFC 2054 and 2055)
529 */
530int
531vfs_setpublicfs(struct mount *mp, struct netexport *nep,
532    struct export_args *argp)
533{
534	int error;
535	struct vnode *rvp;
536	char *cp;
537
538	/*
539	 * mp == NULL -> invalidate the current info, the FS is
540	 * no longer exported. May be called from either vfs_export
541	 * or unmount, so check if it hasn't already been done.
542	 */
543	if (mp == NULL) {
544		if (nfs_pub.np_valid) {
545			nfs_pub.np_valid = 0;
546			if (nfs_pub.np_index != NULL) {
547				free(nfs_pub.np_index, M_TEMP);
548				nfs_pub.np_index = NULL;
549			}
550		}
551		return (0);
552	}
553
554	/*
555	 * Only one allowed at a time.
556	 */
557	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
558		return (EBUSY);
559
560	/*
561	 * Get real filehandle for root of exported FS.
562	 */
563	bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
564	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
565
566	if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp)))
567		return (error);
568
569	if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
570		return (error);
571
572	vput(rvp);
573
574	/*
575	 * If an indexfile was specified, pull it in.
576	 */
577	if (argp->ex_indexfile != NULL) {
578		if (nfs_pub.np_index == NULL)
579			nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP,
580			    M_WAITOK);
581		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
582		    MAXNAMLEN, (size_t *)0);
583		if (!error) {
584			/*
585			 * Check for illegal filenames.
586			 */
587			for (cp = nfs_pub.np_index; *cp; cp++) {
588				if (*cp == '/') {
589					error = EINVAL;
590					break;
591				}
592			}
593		}
594		if (error) {
595			free(nfs_pub.np_index, M_TEMP);
596			nfs_pub.np_index = NULL;
597			return (error);
598		}
599	}
600
601	nfs_pub.np_mount = mp;
602	nfs_pub.np_valid = 1;
603	return (0);
604}
605
606/*
607 * Used by the filesystems to determine if a given network address
608 * (passed in 'nam') is present in their exports list, returns a pointer
609 * to struct netcred so that the filesystem can examine it for
610 * access rights (read/write/etc).
611 */
612static struct netcred *
613vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
614{
615	RADIX_NODE_HEAD_RLOCK_TRACKER;
616	struct netexport *nep;
617	struct netcred *np = NULL;
618	struct radix_node_head *rnh;
619	struct sockaddr *saddr;
620
621	nep = mp->mnt_export;
622	if (nep == NULL)
623		return (NULL);
624	if ((mp->mnt_flag & MNT_EXPORTED) == 0)
625		return (NULL);
626
627	/*
628	 * Lookup in the export list
629	 */
630	if (nam != NULL) {
631		saddr = nam;
632		rnh = NULL;
633		switch (saddr->sa_family) {
634		case AF_INET:
635			rnh = nep->ne4;
636			break;
637		case AF_INET6:
638			rnh = nep->ne6;
639			break;
640		}
641		if (rnh != NULL) {
642			RADIX_NODE_HEAD_RLOCK(rnh);
643			np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh);
644			RADIX_NODE_HEAD_RUNLOCK(rnh);
645			if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0)
646				return (NULL);
647		}
648	}
649
650	/*
651	 * If no address match, use the default if it exists.
652	 */
653	if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0)
654		return (&nep->ne_defexported);
655
656	return (np);
657}
658
659/*
660 * XXX: This comment comes from the deprecated ufs_check_export()
661 * XXX: and may not entirely apply, but lacking something better:
662 * This is the generic part of fhtovp called after the underlying
663 * filesystem has validated the file handle.
664 *
665 * Verify that a host should have access to a filesystem.
666 */
667
668int
669vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp,
670    struct ucred **credanonp, int *numsecflavors, int *secflavors)
671{
672	struct netcred *np;
673
674	lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
675	np = vfs_export_lookup(mp, nam);
676	if (np == NULL) {
677		lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
678		*credanonp = NULL;
679		return (EACCES);
680	}
681	*extflagsp = np->netc_exflags;
682	if ((*credanonp = np->netc_anon) != NULL)
683		crhold(*credanonp);
684	if (numsecflavors) {
685		*numsecflavors = np->netc_numsecflavors;
686		KASSERT(*numsecflavors > 0,
687		    ("%s: numsecflavors <= 0", __func__));
688		KASSERT(*numsecflavors < MAXSECFLAVORS,
689		    ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
690	}
691	if (secflavors && np->netc_numsecflavors > 0)
692		memcpy(secflavors, np->netc_secflavors, np->netc_numsecflavors *
693		    sizeof(int));
694	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
695	return (0);
696}
697